F10-TS: Yes
Rationale
The sender can proactively transmit a packet through both its previously selected UDP endpoint and DERP when path trust expires. The DERP send is not conditional on a UDP send failure or an observed packet loss.
Assessment method
Pinned source inspection and official purpose statement; no runtime experiment
Source context
Tailscale magicsock and packet filter, official privacy statement
Outstanding qualification
Source witness: addrForSendLocked and endpoint.send. Automatic, condition-triggered redundancy; not arbitrary client-requested duplication or guaranteed delivery of both copies.
Public sources
- https://raw.githubusercontent.com/tailscale/tailscale/566f89e0fb2aa4b2f1ebf98761e45e62aa5ef225/wgengine/magicsock/endpoint.go
- https://raw.githubusercontent.com/tailscale/tailscale/566f89e0fb2aa4b2f1ebf98761e45e62aa5ef225/wgengine/magicsock/endpoint.go
- https://raw.githubusercontent.com/tailscale/tailscale/566f89e0fb2aa4b2f1ebf98761e45e62aa5ef225/wgengine/filter/filter.go
- https://raw.githubusercontent.com/tailscale/tailscale/566f89e0fb2aa4b2f1ebf98761e45e62aa5ef225/wgengine/magicsock/magicsock.go
- https://tailscale.com/blog/tailscale-privacy-anonymity
- https://tailscale.com/security
Editorial evidence references
The following identifiers refer to research records not included in this public package; they are not public links.
- round589.html
- round589-sources.json